Belgravia, SW1X and SW1W, and the business of finding the door

The numbering, and why it matters

Belgrave Square runs its numbers in a way that makes sense only from inside it. Several mews share a name with the street they hide behind. A few doors carry a name instead of a number, and one or two carry neither. A companion sent to the wrong end of a cobbled lane at half past ten is not discreet, she is conspicuous, standing under a lamp with her telephone out.

So Tamsin settles three things before she leaves: which street, which door, and what is written by the bell. One message, and the only genuinely awkward thing about this district disappears.

Six hotels on this side of Hyde Park Corner

SW1X 7RL, on Wilton Place. SW1X 7TA, on the corner at Hyde Park Corner. SW1X 7HJ, facing the same junction. SW1W 0JW, behind its own garden near Victoria. Two more, both SW1W 0PS, on Buckingham Palace Road.

No hotel here is a partner of ours and none has been approached. They are listed for orientation, because that is where guests sleep.

Four stations, and the minutes between

Victoria is 5 minutes from the southern edge, with the Circle, District and Victoria lines and the main line platforms above them. Sloane Square is 6 minutes west, Circle and District. Hyde Park Corner is 7 minutes north on the Piccadilly line, and Knightsbridge 8 minutes on the same line. Belgravia is a walkable district and a badly connected one at the same time, which is why nearly every evening here begins with a car rather than a platform.

Who books in SW1X and SW1W

Residents, more than in any other district we attend. People who live here and would rather the evening came to them than the other way about. After them, guests of the two hotels at the park corner, families over for a week in a rented house on one of the squares, and a steady number of people working at the embassies, who ask for exactly what everyone else asks for: someone composed, on time, and entirely uninterested in gossip.

One evening, set down plainly

Seven o'clock on a Tuesday. A guest staying on Chester Square asks for three hours and a dinner that does not need a car. Tamsin suggests Patricia, who knows the upstairs room on Elizabeth Street and prefers an evening with a table in it. Confirmed at ten past seven.

Eight o'clock. Patricia walks from her own flat, six minutes, in linen because the evening is warm. They eat upstairs, take the long way back around Eaton Square, and she says goodnight at the door at eleven. Three hours, £700, handed to her when she arrived and not referred to again.

The three who live among the squares

Lea is small, auburn and far better in a room of six than a room of sixty. Patricia wears linen in daylight and something plainer after eight, and likes evenings that include dinner. Violetta is the tallest woman on our list and the last to raise her voice in any room she is in.

From next door, Lucy and Molly come up from Sloane Street, and Bianka, Margo and Sonya are a few minutes west. Any of them will be at a Belgravia door inside the hour on most evenings.

Quiet, and what it costs to keep

This is a district where a raised voice at midnight carries three streets. Companions arrive on foot from the car, without luggage, and leave the same way. Nothing is left behind in a flat, no photograph is taken anywhere, and no porter or housekeeper is ever told why anyone is there. If a building has a concierge, tell Tamsin and your companion will give only the name you have agreed, which is usually your first name and nothing after it.

The districts either side

Knightsbridge starts at the top of Wilton Place, eight minutes on foot. The designer mile runs south from there towards Sloane Square. Chelsea picks up at the head of the King's Road, ten minutes by car. North across Hyde Park Corner sits the hotel row on Park Lane, five minutes by car and considerably longer on foot. Pimlico and Victoria lie south and are served on identical terms.